It all depends on how you work!

The Smartlink's main advantage is that you'll be able to use only one URL for all the spots you decide to run.

Why?

Because the Smartlink will automatically detect your traffic's GEO, redirecting the best-performing offer to the user of the respective GEO while also guaranteeing the maximization of your revenues.

The disadvantage?

You won't be able to adapt your creatives to the offer since you won't know which is the offer that's actually being redirected.

What about Single Offers?

Both the main advantage and disadvantage are exactly the opposite (advantage: you're able to adapt your creatives to the offer; disadvantage: you have to use a different link per spot and GEO.)

You can always mix both by inserting Smartlinks and Single Offers on your Campaign's rotation!